On the evening of 28 May 1996, Reza Mazlouman, a former Professor of Criminology at Tehran University and Deputy Minister under the Shah, was shot dead in his own apartment in Paris. A friend opened the door to the assassin, who was known to Professor Mazlouman, having introduced himself to the victim previously as an opponent of the regime. The killer waited until the friend had gone, and then fired two shots into Mazlouman's head, killing him instantly.

The friend was able to identify the caller as Ahmad Jayhouni, owner of a video shop in Bonn. The German police, acting on the request of their French counterparts, detained Jayhouni for questioning, and he immediately admitted that he had been to Paris to see Professor Mazlouman on the evening in question, while denying the crime.

It was found, on investigation, that Jayhouni was a high-ranking member of Iran’s Ministry of Intelligence and Security (MOIS) and had been closely associated with the "third floor" of the clerical regime’s Embassy in Bonn, which serves as the MOIS headquarters in Germany.